1. Field of the Invention
This invention relates to slide fasteners and, more particularly, to a slide fastener of the type having continuous coupling elements in the form of coils of filamentary synthetic-resin material. The invention is directed even more particularly to the improved construction of a slide fastener stringer including a coil-type continuous coupling element the turns of which are substantially oval in shape.
2. Description of the Prior Art
In a conventional slide fastener having coil-type continuous coupling elements of the oval-shaped cross section (FIGS. 1 through 4), the coupling elements are stitched onto respective support or stringer tape in such a way that the upper shanks of the scoops formed by each coupling element slope downwardly as they extend rearwardly from the coupling heads toward the bight portions. As a consequence, when the closed slide fastener is bent about an axis extending in the transverse direction of the fastener, the stitches passing over the upper shanks are easy to slip toward the bight portions, thereby giving rise to the possibility of scoop dislodgement or disengagement, as will be later explained in more detail.